2-butoxyethanol (BE) is a member of the glycol ether family and is widely used in many industrial and domestic settings as a solvent. Exposure to this chemical through ingestion, inhalation or contact has produced overt toxic effects in laboratory animals. The immune system is a sensitive target for many toxic chemicals at concentrations far below those that produce observable symptoms. While a significant database is available for the general toxicity of glycol ethers, there is a paucity of information regarding immunotoxicity induced by these chemical solvents. The long-term objectives of this study are to define the immunotoxic effects of BE and its major metabolite 2-butoxyacetic acid (BAA) in BALB/c mice following both in vivo and in vitro exposure and to define the specific mechanism(s) by which immunotoxicity is induced. The specific aims of this proposed study are: 1) to test nonspecific effects of BE and BAA including weight alteration (body, spleen, thymus) and mitogenic stimulation of splenocytes. 2) to test the effects of BE and BAA on the T-dependent B lymphocyte response by utilization of the IgM plaque-forming cell assay. 3) to test the effects of BE and BAA on T cell immunity using the mixed lymphocyte reaction, delayed hypersensitivity using the contact hypersensitivity test and the cytotoxic T lymphocyte response to foreign cells. Also to test the effects of BE and BAA on the innate cellular immune system by determining cytotoxic activity of natural killer cells. Results from this study will provide new information regarding adverse affects of BE and BAA on immune function. Since alterations in immune function often lead to significant alterations in health, the results from the study proposed here may provide a basis for determining whether widespread use of this and possibly other solvents in the same class is safe or if limitations should be considered. In addition, further study into the mechanisms of action of BE could provide information on possible treatments and/or interventions when immunotoxicity occurs.